The present invention refers to a resonant device for a reciprocating compressor driven by a linear motor and to be applied to refrigeration systems of the type used in small refrigeration appliances, such as refrigerators, freezers, drinking fountains, etc.
In the reciprocating compressors with a linear motor, the reciprocating movement of a piston inside a cylinder is effected by means of an actuator, which supports a magnetic component activated by the linear motor. The piston is connected, by means of a usually flexible connecting rod, to a resonant spring, forming with the latter and with the magnetic component, the resonant assembly of the compressor.
The non-resonant assembly of the compressor is formed by a structure lodging the cylinder, the suction and discharge systems of the compressor and its linear motor.
The resonant assembly has the function of developing a reciprocating linear movement in relation to the non-resonant assembly, making the movement of the piston inside the cylinder exert a compressive action on the gas admitted in the compressor, by suction, up to the point in which this gas may be discharged to the high pressure side of the refrigeration system to which the compressor is mounted.
The aim of connecting the piston to the resonant spring by means of a flexible connecting rod is to minimize the transmission of moments of the piston resulting from alignment errors between the center of the resonant spring and the center of the cylinder.
The transmission of said moments resulting from alignment errors make the piston assume an inclined position in relation to the center line of the cylinder, allowing the occurrence of metallic contact between these two components, causing wear and noise due to the attrition created.
The known prior art solutions present a flat resonant spring, of simple construction (FIG. 1), or defined in multiple parallel layers (U.S. Pat. No. 5,525,845), which operates with a long flexible connecting rod of small diameter. These resonant springs, together with the flexible connecting rod, form an assembly difficulty to manufacture and normally high in cost.
Thus, it is an object of the present invention to provide a resonant device for a reciprocating compressor with a linear motor, of reduced cost and easy construction, which minimizes the problems presented by the known prior art constructions.
These and other objectives are achieved by a resonant assembly for a reciprocating compressor with a linear motor, having a piston driven by an actuator, in order to reciprocate inside a cylinder of a non-resonant structure, said cylinder being provided with an end closed by a head, said resonant assembly comprising a resonant element defining, in a single piece, a rod portion, which is flexible and elongated and has a first end coupled to the piston and a second end incorporated to a spring portion affixed to the nonresonant structure according to a plurality of points, which are symmetric in relation to the longitudinal axis of the cylinder and lying on a fixation plane orthogonal to said longitudinal axis of the cylinder.